This invention relates to a sewing data forming device for a sewing machine equipped with a cloth presser device which is to drive a material to be sewed (hereinafter referred to as "a sewing material", when applicable) according to predetermined sewing data.
An industrial sewing machine has been put in practical use which is so designed that, according to sewing data programmed and stored in a memory unit, a sewing material (work) such as a cloth is moved in a predetermined plane while being held, to automatically form a desired sewing pattern on it. The sewing data are stored in a memory medium in the memory unit, to form a variety of sewing patterns on the sewing materials. The memory medium is, for instance, a semiconductor memory, magnetic card, or floppy disk. Data for controlling the operation of the sewing machine are stored in the memory medium in the order of sewing operations.
The control data includes control instructions for controlling an amount of relative displacement of a needle and a cloth, and a sewing speed for every stitch by the sewing machine forming a sewing pattern, and those for controlling the operations of the sewing machine and an electric motor adapted to drive the sewing machine. Control data for one sewing pattern is the assembly of control instructions for a number of stitches. Hence, in order to form a desired sewing pattern on a sewing material with the sewing machine, it is necessary to form sewing data for the sewing pattern in advance and to store them in the memory medium.
FIG. 1 is a perspective view showing a conventional sewing data forming device for a sewing machine which is disclosed by Published Unexamined Japanese Paten Application No. 148582/1985. The device comprises a tablet digitizer 10 including inputting means having a menu section 11, a pattern input section 13, a cursor means 12 such as a mouse to select a desired item from the menu section 11 and to obtain coordinate data from the pattern input section 13. Further in FIG. 1, reference numeral 20 designates an LED (light emitting diode) display panel in the sewing data forming device which comprises a variety of switches and LEDs; 26, a CRT (cathode ray tube) for displaying pattern data; 18, a PROM (programmable read-only memory) section for writing sewing data in a memory medium such as a PROM and for reading the sewing data from the PROM; and 8, an eraser for erasing the sewing data from the PROM.
FIG. 2 shows the menu section 11 in more detail, and the cursor means 12 comprising a reading section 12a and a switch 12b.
The operation of the conventional sewing data forming device will be described with reference to FIG. 3 which is an explanatory diagram showing the arrangement of the device.
A desired sewing pattern is drawn on the tablet digitizer with the mouse 12. In compliance with the sewing pattern thus drawn, sewing data is formed mainly under the control of a CPU 14 and then stored in a RAM 24 temporarily. Then, a PROM writer 16 is operated to write the sewing data thus stored in the RAM 24 to the PROM 18 contained in a PROM cassette 42 through a gate 44. The PROM cassette 42 is loaded in the a sewing machine control device 40 to drive the sewing machine 38. The settings of modes and the procedure of operations in the formation of sewing data are applied, as I/O data, through the gate 44 to the LED display panel 20 to be displayed thereon. The program for writing the input data from the tablet digitizer 10 through the gate 44 in the PROM 18, according to which the CPU 14 operates, has been stored in a system program ROM 22. X and Y coordinate data, which are input data from the table digitizer 10, are stored temporarily in the RAM 24. By operating the input data, sewing data, namely, X and Y coordinate data are obtained. The amounts of variation of the X and Y coordinate data; that is, relative value data thereof are also stored in the RAM 24. The pattern display CRT 26 is provided to monitor the pattern data inputted from the tablet digitizer 10. With the aid of the CPU 14, the sewing data stored in the RAM 24 are converted into image displaying data, which are applied through a gate 33 to an image data RAM 28 so as to be stored therein. Thus, the sewing pattern is displayed on the CRT 26 by a CRT control circuit 46, which facilitates the data inputting operation of the operator.
FIG. 4(a) shows one example of a sewing pattern. Now, a concrete data inputting method will be described. First, a drawing on which the sewing pattern as shown in FIG. 4(a) has been drawn is stuck on the pattern inputting section 13 of the tablet digitizer 10. Thereafter, with the reading section 12a of the mouse 12 set at the "Pattern Input" of the menu section 11, the switch 12b is operated so as to input the sewing pattern. Similarly, in the menu section 11, "Scale", "1", "0", "0", "Stitch length", "3", ".", "0", "Low speed", "Point input" and "Start" are selected successively, to set input conditions. In this case, the scale is set to 100%; that is, the data in the drawing are equal in scale to data inputted, and when two points are inputted, sewing data of 3.0 mm is produced. Further, the sewing speed is made low and an input condition is set to point input.
Thereafter, with the reading section 12a of the mouse 12 set at the origin 0 of the sewing pattern 10a, the switch 12b is operated to input the origin's position. Under this condition, the items in the menu section 11 and the points of the sewing pattern are inputted with the mouse 12 in the following order: "Idle feed", point A.fwdarw.point B.fwdarw."Straight line input", "High speed", point C.fwdarw."Point input", "Middle speed 1", point D.fwdarw.point E.fwdarw."Straight line input", "High speed", point F.fwdarw."Pause", point G.fwdarw."Point input", "Middle speed 1", point H.fwdarw.point I.fwdarw.Straight line input", "High speed", point J.fwdarw."Idle feed", origin 0.fwdarw."End".
FIG. 4(b) shows another example of the circular sewing pattern. The sewing pattern can be inputted by the same method as the sewing pattern of FIG. 4(a). However, the inputting of the sewing pattern shown in FIG. 4(b) is troublesome when compared with the inputting of the one shown in FIG. 4(a), because the sewing pattern is a free curve, and therefore after point A is inputted, point A.sub.1, the remaining points--point A.sub.2, point A.sub.3 . . . point A.sub.41, point A.sub.42, point A.sub.43, point A.sub.44 and point J forming the circular sewing pattern--must be all inputted correctly.
Thus, the inputting of the sewing pattern shown in FIGS. 4(a) and 4(b) has been accomplished. During the inputting operation, the scale value, stitch length, speed instruction values, and inputting method are displayed on the LED display panel 20 whereas the sewing pattern is displayed on the CRT 26.
FIG. 5 is a flow chart showing a data processing operation corresponding to the above-described data inputting operation. When the switch 12b of the mouse 12 is operated in Step S1, the coordinate data are read in Step S2. In Step S3, it is determined whether the data thus read in Step S2 is the one selected from the menu section 11 or whether it is of the sewing pattern. When it is determined that the data is selected from the menu section 1, Step S5 is effected. In Step S5, it is determined which of the items in the menu section 11 has been selected. And, in Step, S6, a process corresponding to the item selected from the menu is carried out. When, on the other hand, the data read in Step S2 is of the sewing pattern in Step S3, the coordinate data read in Step S4 are subjected to arithmetic operation. In Step S7, sewing data is formed, and an operation for displaying the sewing data together with the result of process in Step S6 on the LED display panel is carried out. Thereafter, in Step S8, an operation for displaying the sewing data thus formed on the CRT 26 or writing in the PROM 18 is carried out.
Being designed as described above, the conventional sewing data forming device is difficult to convert a sewing pattern made up of free curves into sewing data high in quality (promising fine seams) with specified stitch length.